" Zero is both a number and the numerical digit used to represent that number in numerals."
- The sum of zero and a negative number is negative.
- The sum of zero and a positive number is positive.
- The sum of zero and zero is zero.
- The sum of a positive and a negative is their difference; or, if their absolute values are equal, zero.
- A positive or negative number when divided by zero is a fraction with the zero as denominator.
- Zero divided by a negative or positive number is either zero or is expressed as a fraction with zero as numerator and the finite quantity as denominator.
- Zero divided by zero is zero.
My personal opinion is that zero divided by zero is undefined so I agree with the modern view. I believe it is undefined because zero divided by zero it is like asking "how many zeros are in zero"; are there 1, 0, infinitely many? Since this question doesn't really make since, I believe zero divided by zero is undefined.